This application seeks competitive renewal of funding for the Yale Skin Diseases Research Core Center (YSDRCC), consisting of a multidisciplinary, collaborative, highly group of 74 investigators (52 established independent investigators) representing 24 different departments/divisions at this institution. These investigators share a commitment to advancing understanding of the etiology and pathogenesis of skin diseases through investigation of both normal and pathologic structure and function of skin. YSDRCC research activities center around two major themes: 1) Cutaneous Immunobiology/Immunopathology/vaccine development with emphasis on both normal T cell : skin interactions as well as those interactions in diseases including atopic and contact dermatitis, lupus erythematosus, scleroderma, cutaneous T cell lymphoma and bacterial (strep, Borrelia), papillomavirus and helminth infections; and 2) Epidermal Biology/Photobiology including studies of normal keratinocyte, keratinocyte/mesenchymal interactions, gene therapy and carcinoma, as well as of normal melanocytes and melanoma. Three Core units (Scid Mouse : Human Xenograft; Cell Culture; and Tissue Acquisition & Analysis) have been established to provide reagents and/or services to multiple YSDRCC investigators. The YSDRCC Pilot/Feasibility Program should continue to enhance the development of new interdisciplinary skin-related investigation by preferentially funding projects involving substantive multidisciplinary collaboration between investigators with complementary interests. The YSDRCC Enrichment Program should continue to provide numerous opportunities for developing new institutional and national collaborative studies. These component parts should each contribute to achieving the YSDRCC's continuing long range goal of creating an environment capable of greatly amplifying understanding of basic cutaneous biology and of a broad variety of skin diseases. To achieve that goal, the YSDRCC's continuing aims are to: 1) stimulate new multidisciplinary interactions; 2) stimulate new investigators to become involved in one or more areas of YSDRCC research; 3) capitalize on potentially important and innovative research opportunities via interdisciplinary pilot/feasibility studies; 4) organize time-consuming techniques, services and/or expensive reagents into cost-efficient core facilities used by multiple investigators; 5) provide a rich training environment; and 6) foster national and international collaborations. A new YSDRCC specific aim will be to facilitate the expansion of imaging capabilities at Yale to include multimodality imaging of skin in vivo.